Summary of Significant Accounting Policies - Deferred Costs (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Segment Disclosure
Number of reportable segments | item	1
Deferred costs and other assets
Deferred financing and lease costs, net	$ 325,720	$ 312,569
In-place lease intangibles, net	188,219	216,330
Acquired above market lease intangibles, net	67,363	75,366
Marketable securities of our captive insurance companies	87,257	111,844
Goodwill	20,098	20,098
Other marketable and non-marketable securities	278,026	698,265
Prepaids, notes receivable and other assets, net	385,576	372,317
Deferred costs and other assets	1,352,259	1,806,789
Deferred Financing and Lease Costs
Deferred financing and lease costs, gross	567,862	533,050
Accumulated amortization	(242,142)	(220,481)
Deferred financing and lease costs, net	325,720	312,569
Amortization, included in statements of operations and comprehensive income
Amortization of deferred financing costs	19,349	21,392	$ 25,159
Amortization of debt premiums, net of discounts	(16,107)	(24,092)	(33,026)
Amortization of deferred leasing costs	$ 43,788	$ 39,488	$ 34,891